Railway signaling apparatus



Oct. 29, 1935. H, G. w 2,019,167

RAILWAY SIGNALING APPARATUS Filed June 14, 1954 INVENTOR. Harold G. Wz'zmer.

B Q/R HIS A TT ORNE Y.

Patented Oct. 29, 1935 umre o star-es PATENT @FFHQE RAILWAY SIGNALING APPARATUS Application June 14, 1934, Serial No. 730,612

18 Claims.

My invention relates to railway signaling apparatus, and particularly to apparatus of the type involving direct current track circuits.

One feature of my invention is the provision,

in apparatus of this character, of novel and improved means for varying the voltage applied to the track circuit in response to variations in the resistance of the ballast, thereby providing substantially constant energization of the track relay under all conditions.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention.

Referring to. the drawing, the reference characters l and l designate the track rails of a stretch of railway, which rails are divided by insulated joints 2 to form a track section 3-4.

Connected across the rails at one end of this section is a track relay TR, which is responsive to direct current but not to alternating current.

Located at the other end of the section is a 26 source of track circuit current B, which, as here shown, is a battery. This battery is connected across the rails of the section through the usual current-limiting impedance 5. The reference character R designates a full-wave rectifier, the

output terminals of which are interposed between the battery B and rail I.

The input terminals of rectifier R are connected with the secondary of a transformer Ti, and the primary circuit for this transformer includes a source of alternating current, such as the secondary of a transformer T2, as well as two spaced conductors Al and A2 which are in contact with the track ballast. It follows that the amount of current which is supplied to transformer TI 40 and so to the rectifier R and the track rails I, I, varies in accordance with the resistance of the track ballast. As the ballast resistance decreases, the amount of rectified current supplied to the track circuit will be increased, and vice versa as the ballast resistance increases, the amount of rectified current supplied to the track circuit will decrease. If the ballast resistance is infinite, no rectified current will be supplied to the track circuit, so that under that condition battery 13 will 60 be the only source of track circuit current.

A fuse F may be inserted in the primary circuit for transformer Tl, if desired, so that if a short circuit should occur between conductors Al and A2, the fuse will blow and will thereby 65 discontinue the supply of rectified current to the track circuit. This fuse will also blow if conductor Al should be connected to rail l at the same time that conductor A2 is connected to rail I If desired, a single auxiliary conductor may be 7 used in place of the two conductors Al and A2, 5 and in this case the upper terminal of the primary of transformer Tl could be connected to rail I a and the auxiliary conductor A2 could be eliminated. I

One advantage of my invention lies in the fact 10 that the track relay TR does not respond to alternating current, and therefore any leakage of a1- ternating current from the conductors Al and A2 into the track circuit cannot cause false op- V eration of the track relay.

Although I have herein-shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing 20 from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track,

a source of direct track circuit current connected 5 across the rails of said section, a full wave rectifier having its output terminals interposed between said source and one of the rails, a transformer having its secondary connected with the 3 input terminals of said rectifier, and a primary circuit for said transformer including a source of alternating current and two spaced conductors in contact with the track ballast.

2. In combination, a section of railway track, a source of direct track circuit current connected 35 across the rails of said section, a full wave rectifier having its output terminals interposed between said source and one of the rails, a transformer having its secondary connected with the input terminals of said rectifier, and a primary circuit for said transformer including a source of alternating current and a portion of the track ballast.

3. In combination, a section of railway track, a source of direct track ciruit current connected 45 across the rails of said section, a full wave rectifier having its output terminals interposed between said source and one of the rails, a transformer having its secondary connected with the input terminals of said rectifier, and means for supplying alternating current to the primary of said transformer at a Voltage which varies in accordance with changes in ballast resistance.

4. In combination, a section of railway track, a source of direct current connected across the rails of said section, a full wave rectifier having its output terminals interposed between said source and one of the rails, and means for supplying alternating current to the input terminals of said rectifier at a voltage which varies in accordance with changes in ballast resistance.

5. In combination, a section of railway track, a source of direct current connected across the rails of said section, a full wave .rectifier having its output terminals interposed between said.

source and one of the rails, and an input circuit for said rectifier including a source of alternating current and two spaced conductors in contact with the track ballast.

6. In combination, a section of railway track, a source of direct current connected across the rails of said section, a full wave rectifier having its output terminals interposed between said source and one of the rails, and an input circuit for said rectifier including a source of alternating current and a portion of the track ballast.

7. In combination, a section of railway track, a source of direct current connected across the rails of said section, a rectifier for also supplying current to the rails of said section, and means for supplying alternating current to the input terminals of said rectifier at a voltage which varies in accordance with changes in ballast resistance.

8. In combination, a section of railway track,

a source of direct current connected across the rails of said section, a rectifier for also supplying current to the rails of said section, and aninput circuit for said rectifier including a source of alternating current and two spaced conductors in contact with the track ballast. 9. In combination, a section of railway track, a source of direct current connected across the rails of said section, a rectifier for also supplying current to the rails of said section, and an input circuit for said rectifier including a source of alternating current and a portion of the track ballast.

10. In combination, a section of railway track, a rectifier for supplying current to the rails of said section, and means for supplying alternating current to the input terminals of 'said rectifier at a voltage which varies in accordance with changes in ballast resistance.

11. In combination, a section of railway track,

a rectifier for supplying current to the rails of said section, and an input circuit for said rectifier including a source of alternating current and two spaced conductors in contact with the track ballast.

12. In combination, a section of railway track, a rectifier for supplying current to the rails of said section, and an input circuit for said rectifier including a source of alternating current and a portion of the track ballast.

13. In combination, a section of railway track, means for supplying direct track circuit current to the rails of said section, and means for regulating the voltage at which such current is applied to the rails comprising two conductors in contact with the track ballast and a source of alternating current connected across said conductors.

14. In combination, a section of railway track, a track relay receiving current from the rails of said section and responsive to direct current but not to alternating current, means for supplying direct track circuit current to the rails of said section, and means for regulating the voltage at which such current is applied to the rails comprising two conductors in contact with the track ballast and a source of alternating current connected across said conductors.

15. In combination, a section of railway track, a track relay receiving current from the rails 01' said section and responsive to direct current but not to alternating current, a source of direct current connected across the rails of said section, a rectifier for also supplying current to the rails of said section, and means for supplying alternating current to the input terminals of said rectifier at a voltage which varies in accordance with changes in ballast resistance.

16. In combination, a section of railway track, a track relay receiving current from the rails of said section and responsive to current of one character but not to current of a different character, means for supplying current of said first character to the rails of said section, and means for regulating the voltage at which said current of the first character is applied to the track rails comprising two conductors in contact with the track ballast and a source of current of said different character connected across said conductors.

17. In combination, a section of railway track, a source of unidirectional current, a rectifier, means including said rectifier for supplying the 40- rails of said section with current from said source, an auxiliary conductor in contact with the track ballast, a source of alternating current, and means including a path from said conductor through the track ballast for supplying current from said alternating source through said rectifier to the rails of said section, whereby the amount of current supplied to the rails from said alternating source will vary in accordance with variations in the resistance of said track ballast.

18. In combination, a section of railway track, a source of direct current, a rectifier, means including said rectifier for supplying the rails of said section with current from said source, a source of alternating current, and means including a path through a portion of the track ballast for supplying current from said alternating source through said rectifier to the rails of said section, whereby the amount of current supplied to the rails from said alternating source will vary in accordance with variations in the resistance of said track ballast.

HAROLD G. WITMER. 

